What was found
STAB JAMMED AT CRUISE FLT, 80 MACH, FLT LEVEL 320. COMPLIED WITH MANUAL, LANDED WITH NO MAJOR PROBLEMS. CAPTAIN STATED THAT DURING CRUISE, PITCH TRIM 1 & 2 DISCONNECTED. TRIED TO ENGAGED PITCH TRIM 1 & 2, BUT KICKED OFF AGAIN. FLT CREW ALSO STATED THAT MANUAL TRIM CONTROL WHEEL BECAME STUCK AND HAD ALOT OF TENSION WHILE AT CRUISE AT FLT LEVEL 320, WITH PITCH TRIMS/AUTO PILOT OFF. FLT CREW DID NOT ATTEMPT TO BREAK CONTROL WHEEL FREE. CONTINUED FLT, AND LANDED WITH FLAPS AT 20, COULD NOT LAND WITH FLAPS AT 40. FOUND THS OIL LOW. DRAINED, SERVICED, CLEANED AND INSPECTED THS JACKSCREW. LUBED SAME AND HINGE POINTS IAW MM 12-22-27-00. RAN THS TROUGH SEVERAL TIMES WITH NO LOCKING OR STIFFNESS.